In a stunning defeat for the labor-backed Working Families Party, City Council Speaker Christine Quinn yesterday announced her opposition to a contentious proposal** that would have mandated paid sick days for private companies.

"Providing sick leave to working New Yorkers is a noble goal, and supporters of this bill have the best of intentions. But now is simply not the right time for a measure that threatens the survival of small-business owners," Quinn (D-Manhattan) said in announcing her opposition, which effectively kills the bill.

"Their businesses are on the brink, and they fear that any new costs will put them under."

While proponents insisted a similar bill in San Francisco has not hurt job growth, Quinn estimated the WFP-backed measure would cost businesses $700 to $1,200 annually.

"At a time like this, those thousands of dollars could be the breaking point for a small-business owner already stretched too thin," she said.

Quinn’s decision was seen as an effort to cater to businesses as she mulls a mayoral run in 2013.

She said she would revisit the idea when the economy improves.

The Partnership for New York City, which represents big businesses, hailed Quinn’s decision.

Quinn "showed real leadership in making the courageous decision to defend the city’s small-business community against another costly mandate," President and CEO Kathy Wylde said.

Proponents of paid sick leave blasted Quinn.

"Speaker Quinn had a chance to really improve the lives of working women, especially low-income women, and chose not to," said famed feminist Gloria Steinem.

Donna Dolan, chairwoman of the state’s Paid Sick Leave Coalition, said Quinn had "turned her back on a critical but modest lifeline that families around the city need — a stunning abandonment of working mothers and parents and the progressive women who have supported her from Day One."

The legislation, which had support from a veto-proof majority of council members, would have required businesses with fewer than 20 employees to offer five paid sick days a year and larger companies nine days.

**Supported by Make the Road New York (MRNY).